Deontay Wilder stopped Luis Ortiz in the 10th round of their first meeting.
But the American has granted Ortiz a second shot at his WBC title.
“Obviously, Deontay had his reasons for taking this fight,” said the Cuban.
“But on Saturday, I’m going to show why that was a mistake. I’m going to be the new heavyweight champion of the world.”
Many have questioned Wilder’s decision to take on such a dangerous opponent with a separate rematch against British star Tyson Fury scheduled for February 2020.
But Wilder said: “I’m the best in the world and I say it with confidence.
“With that being said, I have to give the fans what they’re hungry for, that’s exciting fights.
“The heavyweight division was in a dark place but now it’s on fire and I must keep it going.”
What time does Deontay Wilder vs Luis Ortiz 2 start?
The bout is expected to get underway around 4.30am GMT on Sunday.
How can I live stream Deontay Wilder vs Luis Ortiz 2?
There are two ways to stream the fight in the UK.
Fans will a Sky Sports subscription can stream the event through the Sky Go app.
Streaming is available to non-subscription holders via NOW TV.
NOW TV allows fans to purchase daily, weekly and monthly passes to access Sky Sports channels.
Sky Sports’ coverage begins at 2am.